You would have two IR transistors pointing not quite straight ahead but a little away from each other. They would pan a servo or motor such that they stop when the reading from each Ir transistor was about even, meaning the turret is pointed at the IR led. How far away would that work, roughly, for a normal LED? Are we talking 10ft or 100ft? Has anyone messed with this? If the range is short, is there a better sensor to use besides a camera?

except it will need to follow an IR LED or small cluster of LEDs and be much faster on the response time. I know the servo can move much faster but maybe there is something else limiting the speed like the response time of the phototransistor. Do any of you with experience with this stuff thing that it will be able to work with those modifications?

I just want a response from someone who has already worked with these parts.

Which parts?You haven't specified any parts.

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.Do not send technical questions via personal messaging - they will be ignored.I speak for myself, not Arduino.

OK, here's the answer you want to hear: it will work and it will be effective, and you probably don't need a processor to do it.

Now, what are you going to do about seduction by other environmental sources of IR?

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.Do not send technical questions via personal messaging - they will be ignored.I speak for myself, not Arduino.

I just want a response from someone who has already worked with these parts.

Which parts?You haven't specified any parts.

You're being unnecessarily picky. The level of detail you're asking for isn't relevant but just so you can get over this mental block, here are parts for you: http://www.radioshack.com/product/index.jsp?productId=2049723 They don't matter though because the difference between these parts and other IR phototransistor and IR Leds of the same size is obviously negligible.

What are the other environmental sources of IR light in an office environment?

Well, it's a 150 million kilometres away, but it's a biggie.

Quote

If they exist, then where is an IR LEd emitter/detector pair that use a spectrum that is not typically found?

Illuminators used for IR number plate recognition systems are necessarily heavily filtered to eliminate environmental IR.

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.Do not send technical questions via personal messaging - they will be ignored.I speak for myself, not Arduino.